The present invention relates to a dental contra-angle handpiece with means for illuminating the treatment area, which comprises a front part including the head in which the tool is clamped, this head being provided with at least one miniature bulb, a handle adapted to be detachably connected to said front part, and a rear socket adapted to be fitted to the rear end of said handle and provided with electric contact means adapted to engage matching contact means provided on the rear face of the handle for supplying electric power to said bulb.
It is already known to facilitate the task of dental surgeons by incorporating lighting means adapted to illuminate the treatment area in the handpiece.
In some known device the light source consists of an optical fibre having its output and located beneath the contra-angle head and supplied with light rays from a source consisting of a halogen lamp disposed at the rear end of the contra-angle. However, in such an arrangement a continuous fiber is required for any gap therein which would absorb at least thirty percent of the light intensity and besides the fiber end on the bur side must be safely protected against movement. Furthermore, in this arrangement the contra-angle head must be independent of the fiber support so that, in case of need, this head can be replaced by another head on the handpiece body without changing the optical fiber. Now this may constitute a serious inconvenience, in particular for the assembly of the various component elements of the contra-angle.
Handpieces incorporating one or a plurality of miniature bulbs as a light source are already known, but so far none of the suggested structures provides a simple and reliable electrical connection of the different parts. Since the contra-angle body must be easily detached from the head to permit a quick replacement of the head according to the specific operations contemplated, all the lighting systems proposed heretofore are confronted with the problem of properly interconnecting the various elements. In fact, the conducting leads extending through the contra-angle body must be connected without any difficulty to the conducting leads of the contra-angle head, and the connecting means must be both simple and reliable inasmuch as the handpiece is to be frequently assembled and disassembled in actual service.